ICTP Concentrations Research Articles

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5-14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Increased bone resorption during the first year after stroke.

Significant bone mineral density (BMD) reduction occurs in stroke patients on the hemiplegic side compared with the intact side. To elucidate the pathogenesis of hip fractures in this population, we measured serum markers of bone metabolism and BMD in the stroke patients within 1 year (early group) and between 1 and 2 years after onset of hemiplegia (long-term group). Sera were collected from 51 patients from the early group and 93 patients from the long-term group. All patients had hemiplegia. Sera were assayed for pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker) and bone Gla protein (a bone formation marker). The z score of BMD was determined in both second metacarpals. Serum ICTP concentrations (ng/mL) were higher in the early group (15.4+/-4.1) than in the long-term group (6.7+/-4.4). Bone Gla protein was normal or low in both groups. Multiple regression analysis identified Barthel Index, degree of hemiplegia, and illness duration as independent determinants of ICTP in the early group, whereas Barthel Index, degree of hemiplegia, and serum calcium were determinants of ICTP in the long-term group. There were statistically significant correlations between the z score of the hemiplegic side and age, Barthel Index, degree of hemiplegia, illness duration, 25-hydroxyvitamin D (25-OHD), and ICTP in the early group and between the z score and degree of hemiplegia and 25-OHD level in the long-term group. The pathogenesis of reduced BMD differed between the early and long-term stroke groups. These results suggest that in the early group, increased bone resorption caused by immobilization was responsible for osteopenia on the hemiplegic side, whereas the degree of hemiplegia and 25-OHD level were the determinants of osteopenia in the long-term group.

Decreased Bone Mineral Densities (BMD) and Bone Formation Markers During the First Year After Diagnosis of Insulin Dependent Diabetes Mellitus (IDDM) in Children. 431

We have recently demonstrated that children and adolescents with IDDM present with decreased lumbar spine BMD as early as 5 years after diagnosis. The purpose of this study was to evaluate the bone mineral status in a group of newly diagnosed children (9.0±1.9 months after diagnosis). We studied 10 children (5 males and 5 females) with a mean chronological age of 9.9±1.7 years and a mean glycosilated hemoglobin of 8.6±0.8%. Lumbar spine and femoral neck BMD were measured by dual X-Ray absorptiometry, while bone turnover was asssessed by the determination of the serum concentrations of the carboxy-terminal propeptide of type 1 procollagen (PICP) and the carboxy-terminal cross-linked telopeptide of type 1 collagen (ICTP). Results were compared to those of age, height, weight and pubertal status matched controls. Lumbar spine BMD Z-scores were decreased in our patients when compared to controls (Z-scores were -1.5±0.3, with eight out of ten patients showing values >1SD below the mean). No significant differences were noted in femoral neck BMD and total bone mineral content between groups. Serum PICP levels were decreased when compared to controls(233.6±39.3 vs 375.9±50.7 ug/L; p< 0.002), while serum ICTP concentrations, although increased, were not significantly different(9.3±1.3 vs 5.7±1.5 ug/L). However, PICP and ICTP did not correlate with the lumbar spine Z-score. In summary, early after diagnosis IDDM children present with decreased lumbar spine BMD and decreased bone formation markers.

Effects of gestational age, maternal diabetes, and intrauterine growth retardation on markers of fetal bone turnover in amniotic fluid.

Little is known about the dynamics of bone formation and bone resorption in utero, particularly the normal changes that occur throughout gestation and in clinical situations that result in low bone mass at birth. The objectives of this study were to describe the effects of gestational age on markers of fetal bone turnover, and to investigate whether the reported low bone mass at birth in small-for-gestational-age (SGA) infants and infants of diabetic mothers (IDMs) was associated with biochemical markers of decreased bone formation or increased bone resorption in utero. Bone formation and resorption were assessed by measurement of carboxyterminal propeptide of type I procollagen (PICP) and cross-linked carboxyterminal telopeptide of type I collagen (ICTP), respectively, in 201 amniotic fluid samples. These markers are by-products of type I collagen formation and degradation, respectively, and have been used in the assessment of bone metabolism ex utero. Both PICP and ICTP concentrations in amniotic fluid were inversely associated with gestational age (P < 0.0001). Amniotic fluid concentrations of PICP increased exponentially in relation to infant birthweight (P = 0.008), and SGA infants had lower amniotic fluid PICP concentrations than controls (P = 0.07). The presence of diabetes in the mother was not associated with alterations in amniotic fluid PICP or ICTP concentrations. Although maturational effects on clearance of bone markers from amniotic fluid cannot be excluded, these data are consistent with a high turnover of bone matrix early in fetal life, and a reduction in bone formation when fetal growth is compromised.

Effects of long-term inhaled corticosteroids on skin collagen synthesis and thickness in asthmatic patients

There are only a few studies on the adverse effects of inhaled corticosteroids on the skin in asthmatic patients. Therefore, we evaluated the effect of inhaled corticosteroids on de novo collagen synthesis of skin and bone, skin thickness and the total amount of skin collagen. Twenty seven consecutive new asthmatic patients, on a moderate dose of budesonide or beclomethasone dipropionate, were invited to take part in this prospective study. Radioimmunological analyses of aminoterminal propeptides of type I and III procollagens (PINP, PIIINP, respectively) in suction blister fluid (SBF) of skin and in serum and carboxyterminal propeptide of type I procollagen (PICP) and cross-linked carbox terminal telopeptide of type I collagen (ICTP) in serum were performed at entry and after 3 and 6 months of inhaled corticosteroid treatment. Ultrasound measurements of skin thickness at two sites were performed at entry, at 3 and 6 months and after 1-2 yrs of inhaled corticosteroid treatment in 20 patients, six of whom had been prescribed one or more courses of oral corticosteroids. Skin hydroxyproline of punch biopsies was determined to measure the total amount of skin collagen (males, at entry and at 6 months). Skin thickness and the total amount of skin collagen on the abdomen were unchanged after 1-2 yrs of inhaled corticosteroid use. A slight decrease was observed in the upper arm skin thickness, especially in those subjects who had received inhaled plus oral corticosteroids. The procollagen propeptide concentrations (PINP, PIIINP) were markedly decreased in SBF at 3 months and remained at this level at 6 months. In serum, a slight decrease was seen in the PINP, PIIINP and ICTP concentrations at 3 and 6 months. In conclusion, inhaled corticosteroids decrease the collagen synthesis of skin and bone, but skin thickness and the total amount of collagen in skin are not changed markedly after 1-2 yrs of treatment.

Effects of long-term inhaled corticosteroids on skin collagen synthesis and thickness in asthmatic patients.

There are only a few studies on the adverse effects of inhaled corticosteroids on the skin in asthmatic patients. Therefore, we evaluated the effect of inhaled corticosteroids on de novo collagen synthesis of skin and bone, skin thickness and the total amount of skin collagen. Twenty seven consecutive new asthmatic patients, on a moderate dose of budesonide or beclomethasone dipropionate, were invited to take part in this prospective study. Radioimmunological analyses of aminoterminal propeptides of type I and III procollagens (PINP, PIIINP, respectively) in suction blister fluid (SBF) of skin and in serum and carboxyterminal propeptide of type I procollagen (PICP) and cross-linked carbox terminal telopeptide of type I collagen (ICTP) in serum were performed at entry and after 3 and 6 months of inhaled corticosteroid treatment. Ultrasound measurements of skin thickness at two sites were performed at entry, at 3 and 6 months and after 1-2 yrs of inhaled corticosteroid treatment in 20 patients, six of whom had been prescribed one or more courses of oral corticosteroids. Skin hydroxyproline of punch biopsies was determined to measure the total amount of skin collagen (males, at entry and at 6 months). Skin thickness and the total amount of skin collagen on the abdomen were unchanged after 1-2 yrs of inhaled corticosteroid use. A slight decrease was observed in the upper arm skin thickness, especially in those subjects who had received inhaled plus oral corticosteroids. The procollagen propeptide concentrations (PINP, PIIINP) were markedly decreased in SBF at 3 months and remained at this level at 6 months. In serum, a slight decrease was seen in the PINP, PIIINP and ICTP concentrations at 3 and 6 months. In conclusion, inhaled corticosteroids decrease the collagen synthesis of skin and bone, but skin thickness and the total amount of collagen in skin are not changed markedly after 1-2 yrs of treatment.

Serum concentration of type I collagen metabolites as a quantitative marker of bone metastases in patients with prostate carcinoma

Bone scans, widely used for the detection of bone metastases from prostate carcinoma, can neither quantitate metastatic lesions nor detect osteolytic lesions. Serum concentrations of the carboxyterminal propeptide of Type I procollagen (PICP), the carboxyterminal pyridinoline cross-linked telopeptide of Type I collagen (ICTP), and prostate specific antigen (PSA) were measured by radioimmunoassays in 48 patients with benign prostatic hyperplasia (BPH), 25 patients with prostate carcinoma (PCA) without bone metastases, and 36 patients with PCA and bone metastases. Serum concentrations of PICP were significantly higher in patients with PCA with bone metastases than in patients with BPH or PCA without bone metastases. No significant differences were observed between patients with BPH and those with PCA without bone metastases. Serum ICTP concentrations were significantly higher in patients with PCA than in patients with BPH regardless of the presence or absence of bone metastases. Serum concentrations of PICP, ICTP, and PSA correlated significantly with Soloway's grading system for bone scans. The serum concentrations of PICP and ICTP in patients without bone metastases showed a significant downward trend in response to antiandrogen therapy. These observations suggest that the serum concentrations of PICP and ICTP are quantitative markers of bone metastases from PCA when followed serially in individual patients.

Serum levels of carboxyterminal cross-linked telopeptide of type I collagen (ICTP) in the differential diagnosis of the syndromes of inappropriate secretion of TSH.

Serum TSH assay is a very sensitive and specific index of thyroid hormone (TH) action. Nevertheless, in particular clinical situations, such as those of inappropriate TSH secretion, the measurement of additional parameters evaluating peripheral TH action may be required in order to achieve a correct diagnosis and to assess the impact that thyroid hormone have on a given tissue. The availability of a specific RIA for serum carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) prompted us to study the usefulness of this specific marker of bone resorption in the differential diagnosis of thyroid disorders. Serum ICTP levels were measured in: (a) 10 patients with TSH-secreting pituitary adenoma (TSH-oma), (b) 40 with thyroid hormone resistance (RTH), as well as in (c) 28 patients with Graves' disease or toxic nodular goitre, (d) 31 with autoimmune primary hypothyroidism (PH) and in 8 of them during L-T4 replacement therapy, (e) 23 with central hypothyroidism (CH) during L-T4 therapy and 2 months after its withdrawal, and (f) 26 during TSH-suppressive treatment for goitre or non-metastatic differentiated thyroid cancer. Results were compared with those obtained in 2 groups of normal controls (Group A, n = 61, age range: 23-68 years; Group B, n = 32, age range: 6-15 years). Serum TSH, free T4 (FT4) and free T3 (FT3) were measured by immunofluorometric assays. Serum ICTP was measured by a specific RIA with a sensitivity of 0.5 +/- 0.1 microgram/l, and intra- and interassay coefficients of variation lower than 6%. Mean values of serum ICTP levels in adult controls were 3.8 +/- 1.6 (+/-SD) microgram/l, while in pre- or peri-pubertal controls it was higher than in adults (14.4 +/- 3.1 micrograms/l). Patients with TSH-oma showed significantly increased ICTP levels (8.7 +/- 5.0 micrograms/l, P < 0.001 vs controls), in contrast to those with RTH (3.0 +/- 1.0 micrograms/l, P < 0.02 vs controls). In the differential diagnosis of inappropriate secretion of TSH, ICTP values above 5 micrograms/l strongly indicated the presence of a TSH-oma. Circulating ICTP concentrations were definitely high in thyrotoxic patients (9.4 +/- 4.7 micrograms/l, P < 0.001) and values overlapping the normal range were observed in 8 cases, thus giving to this test a sensitivity and specificity of 71% and 93%, respectively. In contrast, serum ICTP levels in both PH and CH untreated patients were in the normal range, although significantly lower than in controls (2.6 +/- 1.0 and 1.8 +/- 0.7 micrograms/l, P < 0.001). During replacement therapy, ICTP levels rose significantly in both hypothyroid groups (5.1 +/- 2.5 and 2.7 +/- 1.3 micrograms/l). In 2 CH patients, borderline high ICTP levels (7.0 and 7.1 micrograms/l), associated with FT3 concentrations in the upper limit of the normal range, suggested the presence of L-T4 overtreatment; L-T4 dose reduction was followed by the decrease of both indices in a more physiological range (ICTP: 4.2 and 4.7 micrograms/l; FT3: 8.5 and 6.0 pmol/l). In patients treated with TSH-suppressive therapy at the minimal effective dose, ICTP levels did not significantly differ from those observed in adult controls (4.3 +/- 2.0 micrograms/l). The overall correlations between serum ICTP and FT4 or FT3 levels were highly significant (P < 0.001). The present data indicate that serum type I collagen (ICTP) concentrations are modulated by circulating thyroid hormone concentrations. ICTP measurement is particularly useful in the differential diagnosis of the syndromes of inappropriate TSH secretion, in estimating thyroid hormone impact on bone in primary hyperthyroid states, and its longitudinal evaluation may reveal L-T4 overtreatment in patients on substitutive or TSH-suppressive therapy.

Antithyroid therapy improves bony manifestations and bone metabolic markers in patients with Graves' thyrotoxicosis.

Abnormal bone metabolism in patients with Graves' thyrotoxicosis is well documented, but the precise time-course of its recovery remains poorly understood. The present study was undertaken to clarify longitudinal improvement in bony manifestations, especially in cortical bone, and bone metabolic markers in thyrotoxicosis. Two year prospective follow-up study in patients with Graves' disease. Ten consecutive patients with Graves' disease (seven males and three females, of mean (+/-SEM) age 39.3 +/- 3.9 years) were enrolled in the study and treated with antithyroid drugs. Thirteen sex- and age-matched patients with the disease in remission served as controls. Bony manifestations were evaluated both by fine cortical bone striations in the metacarpals on magnified roentgenograms and lumbar bone mineral density (BMD) measurement. Urinary deoxypyridinoline (dPYR) and serum pyridinoline cross-linked telopeptide domain of type I collagen (ICTP) were monitored as markers of bone resorption, as well as serum osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP) and alkaline-phosphatase (ALP) as markers of bone formation. Initial elevated free thyroid hormone levels were normalized within a month of starting therapy. Striation indices of the metacarpals were 1.89 +/- 0.16 before therapy, higher than those of 0.49 +/- 0.12 in the controls (P < 0.0001); the indices gradually decreased to 1.00 +/- 0.20 (12 months) and 0.48 +/- 0.12 (24 months). Lumbar BMD Z-scores increased from -0.22 +/- 0.46 to 0.21 +/- 0.47 (12 months) and 0.68 +/- 0.48 (24 months) (P = 0.0029). Before therapy, urinary dPYR and serum ICTP concentrations were much higher than the control values (dPYR, +553%; ICTP, -396%, P < 0.0001), which declined promptly in the 2nd month. Serum OC, PICP and ALP were also significantly higher than in controls at first (OC, +287%; PICP, +225%; ALP, +196%), and remained elevated until 4 or 8 months. Bone resorption and cortical bone striations occur in untreated patients with Graves' thyrotoxicosis. The bone resorption rapidly ameliorates after normalization of thyroid hormone levels. In contrast, the accelerated bone formation persists for at least 4-8 months, suggesting positive uncoupling of bone remodelling. This dominant bone formation could result in the improvement in cortical bone striations and the increase in bone mineral density of trabecular bone.

Normal serum indices of bone collagen biosynthesis and degradation in small for gestational age infants.

Serum carboxyterminal propeptide of type I procollagen (PICP) and cross-linked carboxyterminal telopeptide of type I collagen (ICTP), new markers of bone collagen type I biosynthesis and degradation, have not been studied in small for gestational age (SGA) infants. In an earlier study, we found a lower bone mineral content (BMC) and decreased serum osteocalcin in SGA than in appropriate for gestational age (AGA) infants, supporting the thesis that decreased fetal bone formation is a cause of lower BMC in SGA. In view of the role of insulin-like growth factor-I (IGF-I) in the regulation of collagen type I synthesis and degradation, and low serum IGF-I concentrations in SGA infants, we hypothesized that serum PICP would be lower and serum ICTP would be higher in SGA than in AGA infants, reflecting decreased bone collagen type I biosynthesis or enhancement of bone collagen type I degradation in SGA. We studied 19 term SGA and 38 term AGA infants that were matched specifically 1:2 by gestation and birth month. There were no differences between SGA and AGA infants in serum PICP nor ICTP concentrations. Serum ICTP was correlated with osteocalcin and with PICP in SGA infants but not in AGA infants. Thus, serum biochemical indices of bone collagen type I biosynthesis and degradation in term SGA infants are similar to those in term AGA infants. These findings are not consistent with the thesis of altered fetal bone collagen type I biosynthesis or degradation in SGA. We suggest that the reduced bone mineral content in SGA infants is predominantly related to a lower supply of minerals rather than defective regulation of bone collagen type I metabolism.

Increased Serum Concentrations of the Carboxy-Terminal-Cross-Linked Telopeptide of Collagen Type I in Patients with AcutePlasmodium falciparumMalaria

We determined serum levels of the carboxy-terminal-cross-linked telopeptide and carboxy-terminal propeptide of type I collagen (ICTP and PICP) in 24 patients with acute complicatedPlasmodium falciparummalaria prior to and 7, 14, 21, and 28 days after therapy by radioimmunoassay in Bangkok, Thailand. Elevated levels of ICTP were observed in patients (mean ± SD concentration 16.7 ± 5.8 ng/ml), compared with normal controls (3.1 ± 1.3 ng/ml), during the acute phase of the disease. In contrast, serum concentrations PICP were not different between patients and controls (168 ± 63 and 144 ± 57 ng/ml, respectively). After therapy serum ICTP concentrations decreased but remained elevated even 28 days after the malaria attack (10.3 ± 2.9 ng/ml). These findings suggest an increased production or release of ICTP inP. falciparummalaria, which could implicate an alteration of extracellular matrix duringP. falciparummalaria.

Increased degradation of type I collagen in acne fulminans.

Acne fulminans is a rare, severe type of acne with unknown etiology. Ulcerative acne lesions, fever and musculoskeletal pain are typical symptoms. In addition, osteolytic or even destructive osteomyelitis-like bone lesions occur in many patients with acne fulminans. In the present study the degradation product (ICTP) of type I collagen, the most abundant collagen of the skeleton, was measured from the sera of patients suffering from acne fulminans. In 3 of 4 acne fulminans patients with active disease, the ICTP concentrations were clearly higher than the range of concentrations in age-matched controls. The mean concentration of ICTP in the acne fulminans patients was 17.6 +/- 6.0 micrograms/I, whereas the corresponding concentration in 6 patients with severe nodular acne was 6.9 +/- 2.1 micrograms/I. Increased uptake of radionuclide in bone scans was observed in all of the 4 patients with acne fulminans. The present results suggest that ICTP is increased in acne fulminans, due to the destruction of bone collagen matrix. ICTP could thus be used for monitoring the activity of acne fulminans affecting the skeleton.

Increased degradation of type I collagen in patients with inflammatory bowel disease.

To assess the mechanisms of osteopenia in inflammatory bowel disease (IBD), the serum markers of bone formation (osteocalcin and carboxyterminal propeptide of type I procollagen (PICP)) and bone degradation (carboxyterminal telopeptide of type I collagen (ICTP)), the bone mineral density (BMD) of the lumbar spine and the proximal femur and calcium intake of 150 unselected IBD patients and 73 healthy controls were investigated. The patients had higher ICTP values (3.69 (SD 1.40) microgram/l) than the healthy controls (3.25 (1.00) microgram/l, p = 0.035), but no differences in serum PICP and osteocalcin between these groups were detected. In the patients, the ICTP, PICP, and osteocalcin values did not have any significant correlation with BMD, but the patients with ICTP values above 3.6 microgram/l had significantly lower Z scores than those with lower ICTP. In the controls, however, a positive correlation between serum ICTP and BMD was found. The ulcerative colitis patients with total colitis had higher values of ICTP (3.96 (1.58) microgram/l) than those with a left sided disease (3.04 (0.86) micrograms/l, p = 0.009). The patients with a history of clinically active disease (n = 20) had higher ICTP (4.58 (1.55) microgram/l) and osteocalcin (12.56 (5.64) microgram/l) values than the patients (n = 130) with quiescent disease (ICTP 3.56 (1.33), p = 0.002, and osteocalcin 9.76 (3.62), p = 0.017). Increased serum osteocalcin, PICP, and ICTP concentrations and reduced BMD Z scores were found in a subgroup of Crohn's disease patients with a history of an active disease (n = 11). Raised serum ICTP and normal values of osteocalcin and PICP in IBD patients show increased breakdown of type I collagen without a compensatory increase in its synthesis suggesting an increased rate of bone degradation as a probable mechanism for osteopenia in IBD. Raised ICTP values are related to reduced bone mineral densities.

Biochemical markers of bone metabolism during distance running in healthy, regularly exercising men and women

The purpose of the present study was to evaluate the effects of long distance running on bone metabolism, using the biochemical markers ICTP (the carboxyterminal cross-linked telopeptide of type I collagen), PICP (the carboxyterminal propeptide of type I procollagen), osteocalcin and bALP (bone specific alkaline phosphatase) as well as parathyroid hormone (PTH) and serum calcium. Twenty healthy, regularly exercising individuals, 10 women and 10 men, participated in a running competition. The mean age was 38 (range 22-55) and 39 (range 22-53) years respectively, the performed distance 15 (range 5-30) and 28 (range 15-30) km respectively, with a speed of 5:30, 5:02 per kilometer respectively. Fasting blood samples were drawn in the morning the day before the race, and also the day after and two days after. A decrease of PICP concentrations among women was evident the day after the competition (from 170 +/- 17 micrograms/l to 158 +/- 17 micrograms/l) which returned to pre-exercise levels two days after the race (167 +/- 19 micrograms/l). Furthermore, a decrease of osteocalcin could be seen in the men one day after the exercise (from 12.1 +/- 1.1 micrograms/l to 10.3 +/- 1.1 micrograms/l). In the men, there was also an increase of ICTP concentrations two days after (3.98 +/- 0.35 micrograms/l) this long-term and demanding exercise, when compared with pre-exercise levels (3.67 +/- 0.28). One single bout of long-term, exhaustive running exercise in well-trained men and women seems to induce a temporary inhibition of bone formation as well as a stimulation of bone resorption.

Elevated serum ICTP concentrations reflect poor prognosis in patients with ovarian carcinoma.

The effect of ovarian carcinoma on the circulating concentration of the cross-linked carboxyterminal telopeptide of type I collagen (ICTP) was studied in 17 patients before and during treatment. ICTP is a complex peptide released from type I collagen, which is the main organic component of bone matrix but also induced in ovarian carcinoma tissue and the peritoneal cavity by the tumour. CA 125 and the aminoterminal propeptide of type III procollagen (PIIINP) were also measured. The preoperative CA 125, PIIINP and ICTP concentrations were pathological in 16 (94%), nine (53%) and seven (41%) patients, respectively. There was a positive correlation between the PIIINP and ICTP levels in serum. After surgery and one course of cytotoxic chemotherapy, the median CA 125 concentration decreased whereas those of PIIINP and ICTP increased. During monitoring of the treatment response, patients with regressive disease showed lower CA 125 concentrations than those with stable or progressive disease. For PIIINP and ICTP there was no clear difference between these response categories, but altogether, simultaneously increasing serum CA 125, PIIINP and ICTP concentrations were consistently associated with poor prognosis.

Effects of infusion of parathyroid hormone and primary hyperparathyroidism on formation and breakdown of type I collagen

The influence of chronic and acute exposure to parathyroid hormone (PTH) on formation and breakdown of type I collagen, using two recently developed radioimmunoassays for serum PICP (the carboxyterminal propeptide of type I procollagen) and serum ICTP (the carboxyterminal telopeptide of type I collagen), have been evaluated. Fasting morning values were obtained from 18 women with primary hyperparathyroidism (HPT) and an equal number of age-matched, healthy controls. A 24-hour infusion of synthetic human parathyroid hormone (PTH 1-38) was performed in 14 healthy females. The patients with HPT had higher values for serum ICTP than the controls (6.0 +/- 3.0 and 4.1 +/- 2.1 micrograms/liter; P < 0.05), whereas the serum PICP concentrations were not different (170 +/- 72 and 151 +/- 65 micrograms/liter; n.s.). During infusion of PTH in healthy subjects, there was an increase of the serum ICTP concentrations (from 3.6 +/- 1.3 to 4.4 +/- 1.8 micrograms/liter; P < 0.001) whereas those of serum PICP decreased (from 185 +/- 78 to 118 +/- 42 micrograms/liter; P < or = 0.0001). The increase of serum ICTP during infusion of PTH was positively related to the increase of serum calcium and other indices of bone resorption, i.e., fasting urinary excretions of hydroxyproline and calcium. The decrease of serum PICP was also related to the changes of serum ICTP and hydroxyproline in urine, serum calcium, and alkaline phosphatase but not to osteocalcin, an established marker of osteoblastic activity. The findings support the fact that serum ICTP is a valuable method for evaluating bone resorption and is also easy to perform.(ABSTRACT TRUNCATED AT 250 WORDS)

P22. Urinary hydroxypyridinium crosslinks and rates of change of bone mass in patients with primary hyperparathyroidism

Substantial changes occur in skeletal metabolism during lactation. These dynamic changes are monitored with biochemical bone markers. The goal of the present study was to follow these changes in lactating cows and to investigate whether cows with a higher milk yield have a higher mobilization rate of calcium from bone. Hydroxyproline, deoxypyridinoline, pyridinoline, and the carboxyterminal telopeptide of type I collagen (ICTP) were chosen as markers for bone resorption, whereas osteocalcin was used as a bone formation marker.Urine and blood samples were collected from cows with a mean standard milk yield of 4900 and 6500 kg, respectively, 14 d before, and 14 d, 1 mo, 1.5 mo, and monthly after parturition.Urinary hydroxyproline, deoxypyridinoline, and pyridinoline concentrations increased with time, but no differences between the two groups were evident. Concentrations of 1,25-dihydroxy vitamin D and ICTP of the two groups showed an increase 14 d after parturition. Furthermore, using multivariate regression models with age and milk yield as covariates, ICTP concentrations were higher in the group with a higher milk yield. In contrast, osteocalcin concentrations decreased 14 d after parturition and returned to prepartum values 1 mo after parturition.The increase of ICTP concentrations in both groups indicates that bone was substantially resorbed. At the same time, probably less Ca was embedded in bone, as indicated by the decrease of the osteocalcin concentrations. In conclusion, cows showed increased bone resorption around parturition, and cows with higher milk yield mobilize calcium more actively from bone than cows with lower milk yield.

Radioimmunoassay for the pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen: a new serum marker of bone collagen degradation

We developed a radioimmunoassay (RIA) for the carboxy-terminal telopeptides of type I collagen (ICTP), cross-linked with the helical domain of another type I collagen molecule, after isolation from human femoral bone. The cross-linked peptide was liberated by digesting insoluble, denatured bone collagen either with bacterial collagenase or with trypsin, and purified by two successive reversed-phase separations on HPLC, with monitoring of pyridinoline-specific fluorescence. The purity of the peptide was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its origin in the type I collagen fibers was determined by amino-terminal amino acid sequencing. Polyclonal antibodies and a separation reagent containing second antibody and polyethylene glycol are used in the RIA. An immunologically identical, somewhat larger antigen is present in human serum; its concentration increases in multiple myeloma and in rheumatoid arthritis. The ICTP antigen seems to be cleared from the circulation by the kidneys, because glomerular filtration rates that are two-thirds of normal or less are associated with increased circulating ICTP concentrations. The CVs of the method are between 3% and 8% for a wide range of concentrations. The analysis of 40 serum samples can be completed in 4 h.